Thats so weird that it doesn't lather. I can't even claim to be an expert, but the batch we made lathers nice. Though I dont think its as clear as in that video either, but you saw the pics.
Here is what we did (this was all in grams
Castor 240g (30%)
Coconut 160g (20%)
Palm Oil 400g (50%)
Mixed with 353 g of a 32.5% ww lye solution - but whatever gets you to 1% (ONE percent) superfat. Which I thought was strange but makes sense considering that M&P is supposed to be able to mix with things later.
Stick Blend in the crockpot to a good trace
Hot process to zap free - it is critical that the saponification is finished here.
Then keep on medium to high in crockpot and dilute slowly with
380 g PG and 70g VG stir until clear and all the lumps gone edit to add: do not stickbblend here, just stir.
Then add 420 g of a 57% sugar solution (240 g sugar and 180 g water) and stir to homogeneity.
Stir to clear and pour into molds